Alternative pathways of xanthone biosynthesis in cell cultures of Hypericum androsaemum L.
The biosynthesis of xanthones was studied in cell cultures of Hypericum androsaemum L. We have detected a new benzophenone synthase, for which the preferred substrate is benzoyl-CoA, itself supplied by 3-hydroxybenzoate:coenzyme A ligase. The stepwise condensation of benzoyl-CoA with three molecules of malonyl-CoA, catalyzed by benzophenone synthase, yields 2,4,6-trihydroxybenzophenone. This intermediate is subsequently converted by benzophenone 3'-hydroxylase, a cytochrome P450 monooxygenase. These biosynthetic steps, leading to the formation of 2,3',4,6-tetrahydroxybenzophenone, represent an alternative pathway to that recently proposed for cell cultures of Centaurium erythraea [Peters et al., Planta (1997) in press].
Schmidt
W
W
Institut für Pharmazeutische Biologie, Bonn, Germany.
Beerhues
L
L
D000214:Acyl Coenzyme A / Q000378:metabolism; D019735:Carbon-Carbon Ligases / Q000032:analysis / Q000378:metabolism*; D002478:Cells, Cultured; D003066:Coenzyme A Ligases / Q000032:analysis / Q000378:metabolism; D065607:Cytochrome P-450 Enzyme Inhibitors; D004791:Enzyme Inhibitors / Q000494:pharmacology; D062385:Hydroxybenzoates / Q000378:metabolism; D006899:Mixed Function Oxygenases / Q000037:antagonists & inhibitors / Q000378:metabolism; D015394:Molecular Structure; D010944:Plants / Q000378:metabolism*; D013379:Substrate Specificity; D014966:Xanthenes / Q000378:metabolism*
D000214:Acyl Coenzyme A; D065607:Cytochrome P-450 Enzyme Inhibitors; D004791:Enzyme Inhibitors; D062385:Hydroxybenzoates; D014966:Xanthenes; C032948:3-hydroxybenzoic acid; C037817:benzoyl-coenzyme A; D006899:Mixed Function Oxygenases; D003066:Coenzyme A Ligases; D019735:Carbon-Carbon Ligases; C098887:benzophenone synthase